Malaysia Airlines Flight 370 Probe Sharpens Focus on Sabotage

Malaysia's leader says communications systems on Flight 370 were cut off by "deliberate action." U.S. officials are investigating whether a third system, on the plane's lower deck, was also compromised. WSJ's Jason Bellini explains. Image: AP

By

Andy Pasztor

Jon Ostrower

The investigation into the disappearance of Malaysia Airlines Flight 370 sharpened its focus on sabotage, according to aviation and industry officials, amid strong indications that one or more people on the plane deliberately changed its course and tried to mask its location.

Officials suspect two different systems were shut off after the plane took off last weekend, one shortly after the other, people familiar with the investigation said. About an hour into the flight, the plane's transponders stopped functioning, making...